1. Field of the Invention
One embodiment of the present invention relates to a light-emitting device, an electronic device, and a lighting device which include a light-emitting element in which a light-emitting layer capable of emitting light by application of an electric field is provided between a pair of electrodes.
Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, a method for driving any of them, and a method for manufacturing any of them.
2. Description of the Related Art
Light-emitting elements which include organic compounds as light-emitting layers and are characterized by thinness, lightweight, fast response, and direct current driving with low voltage are expected to be applied to next-generation flat panel displays. In particular, a light-emitting device in which light-emitting elements (e.g., organic EL elements) are arranged in a matrix is considered to have advantages of a wide viewing angle and excellent visibility over conventional liquid crystal display devices.
In an organic EL element, voltage application between electrodes, between which a light-emitting layer is interposed, causes recombination of electrons and holes injected from the electrodes, which brings a light-emitting substance (an organic compound) into an excited state, and the return from the excited state to the ground state is accompanied by light emission. Since the spectrum of light emitted from a light-emitting substance is peculiar to the light-emitting substance, use of different types of organic compounds as light-emitting substances makes it possible to provide light-emitting elements which exhibit light of various colors.
In the case of light-emitting devices for displaying images, at least three-color light, i.e., red, green and blue light, is necessary for reproduction of full-color images. Furthermore, to enhance image quality with favorable color reproducibility, various efforts such as use of a microcavity structure and a color filter have been made to improve color purity.
As a way to achieve full-color display, for example, there is a method in which light-emitting layers for different colors are deposited in pixels side by side. The light-emitting layers are vapor-deposited on only predetermined pixels using a shadow mask. In this case, to reduce cost by reducing the number of steps, a structure in which layers except the light-emitting layers, e.g., a hole-transport layer, an electron-transport layer, and a cathode, are formed to be shared among a plurality of pixels, is disclosed (for example, see Patent Document 1).